Reusing Yeast

[teddyearp]

In my travels about this site, I've seen plenty of folks talk about tossing their cider on the yeast cake from either a batch of beer or even one of cider.

My question is, do you need any more nutrient and/or pectic enzyme if you usually use these things?

 

[bleme]

Nutrient is always a smart choice (can't hurt right?) and the cake wouldn't affect how much pectic enzyme you need.

 

[Sequoiacider]

You can toss it on the previous yeast cake and can end up with good results after doing so, but there is a lot of other stuff in that yeast cake besides yeast and can cause off flavors. It also often times is done by starting your new batch in a fermenter that has not been cleaned and sanitizied from your previous batch, which can end up causing very undesirable results.

A better method of reusing yeast is to follow the "harvest and wash" method. Its fairly simple, and will give you consistent results. It will also allow you to store the yeast for later use.
1) Make some clean, microbe-free water. Easiest method is to boil water, put it in a jar, then let it cool. If you have a sub-micron water filter made for removing all contaminants including bacteria, then that can be used instead. Also thouroughly sanitize some empty jars.
2) Pour some of that clean water into the fermenter onto the yeast cake. Give it a swirl to make it into a slurry. Wipe the lip of the fermenter with some alcohol to ensure there are no contaminants on the lip, then pour the slurry it into some jars.
3) Allow the jars to sit on the counter for approximately 30-40 minutes. You will notice some heavier sediment settling to the bottom of the jars, and the bulk of the liquid remaining opaque. The heavy sediment that settles quickly is primarily fruit/beer sediment, dead yeast, and other undesirable stuff. Live yeast will still remain suspended in the liquid at this point.
4) Carefully pour (decant) the opaque liquid off of the sediment into another set of clean jars.
5) Set the jars with the liquid into the refrigerator for at least a few days. The stuff that was making the liquid opaque will settle to the bottom, with clear liquid above it. Carefully pour off the clear liquid. The sediment that you are now left with should be white or off-white.
6) You now have a washed yeast slurry that can be pitched directly into a new batch.

I have found that this slurry will also keep very well in the refrigerator, and have successfully used yeast that was harvested in this manner up to 9 months later with great results. If you are planning on storing it, then leave a small amount of the clear liquid on top of the final sediment during storage. Also, when using some that has been stored for a while, be sure to inspect it before pitching it to ensure that you didn't accidentally end up with mold on your yeast. If you were careful about keeping everything clean and sanitized during the process, then there shouldn't be any.

I always recommend using Yeast Nutrient (I use Organic Non-DAP nutrient, Fermaid-O), though that is up to the brewer. Use of pectic enzyme is also up to the brewer. Weather you are using fresh yeast or reusing old yeast will not factor in to the decision of weather to use Nutrient or Enzyme.

 

[madscientist451]

I just dump the juice in on top of the yeast cake, I don't use yeast nutrients in cider. I add the pectic enzyme before pressing the apple pulp, but usually don't add any if I'm using purchased juice.
I stopped "washing" my yeast year ago.
Haven't had any issues.
Your results may vary, so do what works for you.

 

[Coldfrog]

I just dump the juice in on top of the yeast cake, I don't use yeast nutrients in cider. I add the pectic enzyme before pressing the apple pulp, but usually don't add any if I'm using purchased juice.
I stopped "washing" my yeast year ago.
Haven't had any issues.
Your results may vary, so do what works for you.

I dump a new batch of juice on the yeast cake if I like what I am transferring out of the fermenter and have room for another batch at the time. I’ve never had an issue with contamination or off flavors, though I pressure transfer with CO2 so the fermenter is never open to atmosphere except for when I add the new juice.

 

[bmd2k1]

Other than cost (for the pricier yeasts) -- are there benefits to reusing yeast?

 

[blasterooni]

I have used both of the methods described above, and yeast that I have dried post harvest, and all three have given me results as though I used "fresh" yeast from the store. I have also poured some juice onto the yeast cake, gave it a swirl and added it to juice in a freshly cleaned and sanitized carboy. Probably doesn't do anything to do this since I am pouring whats in the dirty carboy into the clean one...more psychological than anything else

 

[MarkKF]

Other than cost (for the pricier yeasts) -- are there benefits to reusing yeast?

I’ve only used it for reusing wild yeast.

 

[Sequoiacider]

Other than cost (for the pricier yeasts) -- are there benefits to reusing yeast?

Same for me. I do this for wild yeasts. For typical(cheap) commercial yeasts there isn't really any reason to reuse. For more expensive yeasts, this can allow you to propagate and keep it rather than having to buy more.

 

[teddyearp]

I suppose I was just being lazy. And then since I haven't really done anything much different in the way of source juice and/or additives, I thought this would be a nice lazy way to try something different, lol. So I did.

 

[bolus14]

I would just recommend that once it used for cider don't reuse it for beer. Once yeast gets used to simple sugars it may struggle with the maltose in beer. I have had no issues using yeast from beer in ciders, they adapt better going from complex sugars to simple sugars.

Another reason besides cost is better fermentation. Assuming your not making a starter with new yeast, washing or pitching on a yeast cakes gives more yeast for fermentation. Some have stated issues with sulfur sometimes and equating it to under pitching or lagging fermentation, with a higher population of healthy yeast that isn't an issue.

 

[MarkKF]

Another reason besides cost is better fermentation. Assuming your not making a starter with new yeast, washing or pitching on a yeast cakes gives more yeast for fermentation. Some have stated issues with sulfur sometimes and equating it to under pitching or lagging fermentation, with a higher population of healthy yeast that isn't an issue.

That sounds like an argument for using a yeast starter. I always do when using commercial yeasts and a 5-6 batch. I probably would even with washed yeast.